Two identical Garret t4 turbos I rebuilt.

I just finished the final clocking today, and noticed that one turbo does turn, but has a slight drag to it.

I took it all apart again, checked everything, and re-assembled, but it still slightly drags.

Its not touching the housing at either end. Also, this is NOT a ball bearing turbo, just the old bushing type.

Could it be the new bushings are a bit tight on that one turbo shaft, and will loosen up over time?

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

It could be as simple as one of the ring seals being pushed against the side of the groove. I'd try it and check it often, it'll probably free right up.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Many times it can be the thrust. If it has no detectable axial play it could be the thrust binding slightly. Does it have the typical radial movement? It should have a few thousandths axial movement dry.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

I'll check it again tomorrow.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Sorry guys, but I worked on rebuilding a 5 speed auto transmission today, and I'm beat. I will check in/out movement, but I know there is a tiny bit of side to side movement, I think it was around .02 on both according to the dial indicator.

I think you're right in the thrust area being the problem.

I forgot to mention I had to clearance the turbine shield. It was sitting too high above the body so that the seal wouldn't seat in the housing.

I held it to the flat side of my bench grinding wheel, and took enough off so that looked like it was sitting on top of the housing. Of course it might have needed just a bit more clearance.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Finally got around to taking the turbo off.

Turned out the turbine ring seal had cocked on the shaft when I pushed it in. So I ordered another ring, and will have to wait.

One problem, and this was a used pair of turbos was that the turbine shield was sitting too high over the bore which messed with the ring install.

So I machined it down more to where it just sits on top of the housing. Too bad I goofed up the damned ring.

However I promise I WILL update this as soon as the new ring arrives. I hate people who don't post if/how their repair went.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Question, is there a trick to get the ring into the housing.

I know the one turbo I used a very small flat screwdriver to push the ring ends together, but it was still a bitch to do while pushing the shaft into the housing.

I would guess that since there is a bevel in the housing that the seal is supposed to just be pushed into the housing on the shaft, but in the case of the problem turbo, the seal ended up bent. I didn't think to look for a chamfer on the ring/seal itself, but I don't think there was one.

So what do you guys use to get the ring/seal in the housing without damaging it?

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Well I got the new seal in today, and installed it.

The turbines were still a bit tight so I pulled the seal, and lightly sanded the grooves on the shaft to remove any burrs.

Doing that did help free it up some, but the blades still won't free wheel like the other turbo, but it isn't as tight as it was before.

For now I'm just going to run it as it, and see if it will loosen up after driving it a few miles.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Ok, update:

Today I took the turbo out, and removed the turbine seal/ring.

I spun the turbine in the housing without the seal, and it spun freely.

I put the ring back in, and turned the ring in the groove on the shaft, and felt it grab in places. I took a small file, and d-burred the lands of the ring groove until the ring didn't bind anywhere.

After putting it all back together, while still on the bench, I spun the turbine with an air wrench, while pressing forward just a bit.

After re-assembly the turbine now spins like it should. I checked again after installing in the truck. With the engine running, and it was spinning just fine.

Question, that ring on the turbine shaft IS THE SEAL that prevents oil from leaking out of the turbo.........correct?

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Yes, that's the seal on the turbine side.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Thanks. Maybe that will cure the leaking oil.

 

Re: I just finished rebuilding two T4 turbos. One spins freely, the other does spin,

Well, it cured the leaking oil...........